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E. K. Rideal

Bio: E. K. Rideal is an academic researcher. The author has contributed to research in topics: Permeability (electromagnetism). The author has an hindex of 1, co-authored 1 publications receiving 18 citations.

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Journal ArticleDOI
TL;DR: In this article, the surface tension of aqueous solutions of common atmospheric organic compounds (β-pinene, n-hexanol, eugenol, and anethole) was measured and it was shown that these compounds produce films with properties similar to those of the more well known surfactants.
Abstract: Surface-active organic molecules are common constituents of atmospheric aerosol particles, raindrops, and snowflakes. If these compounds are present as surface films, transfer of gases into the atmospheric water systems could be impeded, evaporation could be slowed, and the aqueous chemical reactions could be influenced. To investigate these possibilities, we have reviewed the chemical literature pertaining to organic films on aqueous surfaces: their composition, structure, properties, and effects. We then review the surface-active organic compounds in atmospheric water. We report the results of new measurements of surface tension of aqueous solutions of common atmospheric organic compounds (β-pinene, n-hexanol, eugenol, and anethole) and demonstrate that the compounds produce films with properties similar to those of the more well known surfactants. We conclude that organic films are probably common on atmospheric aerosol particles and that they may occur under certain circumstances on fog droplets, cloud droplets, and snowflakes. If present, they will increase the lifetimes of aerosol particles, fog droplets, and cloud droplets, both by inhibiting water vapor evaporation and by reducing the efficiency with which these atmospheric components are scavenged. The presence of the films will not cause a significant reduction of solar radiation within the aqueous solution. It appears likely, however, that the transport of gaseous molecules into and out of the aqueous solution will be impeded by factors of several hundred or more when organic films are present. Since incorporated gas molecules provide much of the oxidizing potential of atmospheric water droplets, the organic films will play a major role in droplet chemistry by strongly inhibiting solution oxidation.

417 citations

Journal ArticleDOI
TL;DR: In this article, it was shown that the evaporation rate of a liquid is determined, inter alia, by its equilibrium vapour pressure and by the actual pressure of vapour just above the surface.

147 citations

Journal ArticleDOI
TL;DR: The cis-9-octadecen-1-ol film had little effect on the net uptake rate of acetic acid vapor into solution; however, the uptake rate was reduced by almost one-half by an interfacial film of 1-triacontanol.
Abstract: Recent field studies of collected aerosol particles, both marine and continental, show that the outermost layers contain long-chain (C ≥ 18) organics. The presence of these long-chain organics could impede the transport of gases and other volatile species across the interface. This could effect the particle's composition, lifetime, and heterogeneous chemistry. In this study, the uptake rate of acetic acid vapor across a clean interface and through films of long-chain organics into an aqueous subphase solution containing an acid−base indicator (bromocresol green) was measured under ambient conditions using visible absorption spectroscopy. Acetic acid is a volatile organic compound (VOC) and is an atmospherically relevant organic acid. The uptake of acetic acid through single-component organic films of 1-octadecanol (C18H38O), 1-triacontanol (C30H62O), cis-9-octadecen-1-ol (C18H36O), and nonacosane (C29H60) in addition to two mixed films containing equimolar 1-triacontanol/nonacosane and equimolar 1-triacon...

44 citations

Journal ArticleDOI
TL;DR: Records of impedance changes show that effects of TEA and DDT on components of ionic conductances are similar to those found in other axons by voltage clamp measurements.
Abstract: Crayfish giant axons remain viable following internal perfusion with a mixture of fluoride and citrate salts. The relative favorability of various internal anions, and the dependence of resting and action potentials on internal cations are both similar to results on internally perfused squid axons. TEA widens the falling phase of the spike only from inside the axon, while DDT is active from either side of the membrane. Records of impedance changes show that effects of TEA and DDT on components of ionic conductances are similar to those found in other axons by voltage clamp measurements. Tannic acid perfused internally at a concentration of the order of 10 μM produces spontaneous activity, and a progressive increase in spike width. After 30 minutes, action potentials are “cardiac” type and are up to several minutes in duration. Records of impedance changes, and data from rapid changes in external ionic concentrations, suggest that the plateau phase of the spike is due to a maintained increase in sodium conductance. Since tannic acid is capable of crosslinking proteins and “rigidifying” protein monolayers, it is suggested that its effects on the axon may be the result of an interference with a conformational change in a membrane protein or protein-phospholipid complex during excitation.

36 citations

Book ChapterDOI
Martin Blank1
01 Jan 1962
TL;DR: In this paper, the activation energy for the diffusion of a gas molecule through the whole monolayer was found to be about 360 cal/mole, in satisfactory agreement with the results for water vapor.
Abstract: Close-packed monolayers of hexadecanol, octadecanol, octadecanoic acid, and heptadecylamine at the gas-water interface, which are known to retard the passage of water vapor, have been shown to retard the passage of other gases as well. The permeabilities of these monolayers to carbon dioxide, to oxygen, and to nitrous oxide are of the same magnitude (about 10-3 cm/sec) and considerably lower than the permeability to water vapor. The relative permeabilities of the different monolayers, however, agree with the literature on water vapor. The activation energy for the diffusion of a gas molecule through the whole monolayer is of an order of magnitude lower than that found for water permeability, but the activation energy per CH2 group was found to be about 360 cal/mole, in satisfactory agreement with the results for water vapor. The differences in the magnitudes of the permeabilities and of the activation barriers of whole monolayers to various gases are explained tentatively on the basis of the interfering effect of water vapor. The biological implications of this work are briefly discussed.

21 citations